From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750985AbWBWLhX (ORCPT ); Thu, 23 Feb 2006 06:37:23 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750988AbWBWLhX (ORCPT ); Thu, 23 Feb 2006 06:37:23 -0500 Received: from mail05.syd.optusnet.com.au ([211.29.132.186]:19124 "EHLO mail05.syd.optusnet.com.au") by vger.kernel.org with ESMTP id S1750924AbWBWLhX convert rfc822-to-8bit (ORCPT ); Thu, 23 Feb 2006 06:37:23 -0500 From: Con Kolivas To: Emmanuel Pacaud Subject: Re: isolcpus weirdness Date: Thu, 23 Feb 2006 22:37:13 +1100 User-Agent: KMail/1.9.1 Cc: Frederik Deweerdt , linux-kernel@vger.kernel.org References: <1140614487.13155.20.camel@localhost.localdomain> <200602232100.46551.kernel@kolivas.org> <1140691905.8314.21.camel@localhost.localdomain> In-Reply-To: <1140691905.8314.21.camel@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 8BIT Content-Disposition: inline Message-Id: <200602232237.13470.kernel@kolivas.org> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thursday 23 February 2006 21:51, Emmanuel Pacaud wrote: > Le jeudi 23 février 2006 à 21:00 +1100, Con Kolivas a écrit : > > On Thursday 23 February 2006 20:55, Emmanuel Pacaud wrote: > > > Le mercredi 22 février 2006 à 22:18 +0100, Frederik Deweerdt a écrit : > > > > On Wed, Feb 22, 2006 at 02:21:27PM +0100, Emmanuel Pacaud wrote: > > > > > What's wrong ? > > > > > > > > Are you able to reproduce the same behaviour after disabling HT in > > > > the kernel config? > > > > > > I think HT is disabled in kernel config, since I only see 2 cpus. > > > > > > In fact, I've tried to enable HT, but did'nt succeed. HT is enabled in > > > BIOS, but I'm not sure about exact things I must set at kernel config > > > level for hyperthreading. I've tried to set/unset CONFIG_SCHED_SMT, but > > > that changes nothing (no hyperthreading, isolated cpu is always cpu0). > > > > > > Here's attached my config file. > > > > CONFIG_ACPI is not set > > > > You need ACPI to enumerate hyperthread siblings. That's why HT never gets > > enabled for you. > > Following your advice, I've set CONFIG_ACPI, and now, isolcpus works > fine, when hyperthreading is activated. > > But, I'm trying to build a real time system where hyperthreading is not > desired. So, I've tried to disable HT in BIOS, and the result is the > same as when ACPI is not enabled in kernel config: isolated cpu is > always cpu0. > > On the same machine, which is originally a Scientific Linux 4, I've > tried with distribution supplied kernel (a customized 2.6.9 with smp/HT > enabled): isolcpus works fine, even with HT disabled at BIOS level. Sorry I was only explaining why hyperthreading wasn't working with your config. I don't know anything about your problem specifically. Cheers, Con